Sunnyvale (CA) - Earlier today, TG Daily ran an article entitled Intel attacked over Xeon 5500's power-efficiency. Shortly thereafter, Intel contacted TG Daily's owner, Wolfgang Gruener, to address some concerns over positions taken in that article regarding Nehalem's power figures. As a result of that phone call, Gruener has allowed Intel to prepare a response, which we would publish on behalf of Intel.
Below is Intel's response, unedited and conveyed in full:
When Intel introduced the Nehalem based Xeon products earlier this week, it represented the culmination of a long road in designing the part. Since day 1 in building Nehalem, one of the key philosophies we had when building it has been overall power/performance efficiency. Efficiency of course is not the sole metric of interest – the most power/performance efficient part probably is something in a cell phone, but that doesn't meet the performance needs of a data center. So, our goal was deliver record-shattering performance but be more power efficient than recent generations of products. Having a philosophy is nice, but what did it mean in the final product:
- As architects, we only pursued features that were power/performance efficient. This may sound like common sense, but the reality is that in the "good old days" we chased performance at any cost. With Nehalem, we had to change our mindset. If we had a feature that brought significant performance, but was not power/performance efficient, we did not implement the feature. Instead, we focused our efforts on features like Hyper-Threading (the ability to run multiple software threads simultaneously within a single core) which can bring significant performance (up to 30% on many server benchmarks) for very little power cost.
- A second goal we had was to build Nehalem such that it fits in the exact same power envelope as the previous generation products. By doing that, customer now have an option – Take advantage of the massive performance goodness of Nehalem by simply upgrading to it within the same infrastructure that they already have (cooling, etc.) since the power envelope is the same, or they can choose lower power envelope products, take the power savings, and still get either the same or better performance. It provides flexibility to the customer.
- Finally, we introduced some unique features to Nehalem focused on power and performance. First, we said that it made no sense that cores that were not being used by software take power. So, we added our "integrated power gates" which allows us to literally cut the power to cores dynamically so that when you are running software that doesn't use all threads or when your CPU is idle (like they often are in many data centers), you are not paying additional power. And once we did that, we also added our Turbo Boost Technology, which converts power headroom to extra performance w/o requiring any intervention from the user. So, with the combination of these two features, turbo allows you to get higher performance and complete a task faster. Then, with the power gates, you can go to an idle state that takes very little power.
So, in architecting Nehalem, we set out to be the world's best server CPU both performance-wise and power/performance efficiency wise. Take a look at benchmark results like SpecPower that show both the power and performance story together and see what you think.
http://www.intel.com/performance/server/xeon/summary.htm
Ronak Singhal
Senior Principal Engineer, Digital Enterprise Group, Intel.
TG Daily would like to thank Intel for taking the time to prepare this statement for publication on our website. And to our readers, please post any comments below.
Thank you,
TG Daily's Managing Editor
Rick C. Hodgin
Workout of the Day
